1. Field of the Invention
This invention relates to a ceramic filter comprising a plurality of three-terminal, dual-mode filter elements which are connected with each other in such a manner that the input and output impedances of the filter are increased.
2. Description of the Prior Art
There have conventionally been proposed filters comprising a plurality of three-terminal ceramic filter elements connected with each other, wherein the output terminal of one of the filter elements is connected with the input terminal of another of the filter elements, and a coupling capacitance is connected between the ground and the connection point between said output and input terminals.
However, such a conventional arrangement has such a disadvantage that limitation is laid thereupon in respect of matching with peripheral circuits due to the fact that the input and output impedances thereof are as low as about 300 to 500 .OMEGA. for the reason which will be described later.